Examples of cell culture include monolayer culture (adhesion culture), in which cells are adhered to incubators for propagation, and suspension culture, in which cells are propagated in a suspended state.
Most animal cells adhere to surfaces in order to grow and have a growth speed that is even slower than that of microorganisms, and accordingly, productivity is low and the animal cells are easily contaminated by microorganisms during culturing.
However, in cell plate adhesion culture, it is difficult to maintain a seal, and thus cells are easily contaminated after a cell obtaining process over a predetermined period of time in existing processes.
Further, a separate sealing unit needs to be provided when the cultured cells are moved to the outside of a laboratory, but there is no successful case where sealing is perfect, and vessels are mostly transported in order to move the cells.
However, when the vessels are transported, another passage occurs, thus making it difficult to maintain uniformity of the cultured cells.
Meanwhile, a protease such as trypsin is used to detach the cells that have adhered to the inside of the vessel to be cultured.
The enzyme dissolves the connection surface with the adhesion surface to destabilize adhesion of the cells, and entails various problems such as a long enzyme treatment time, changes in the properties of the cells and the death of cells owing to toxicity of the enzyme.
The extent of change in the properties of cells is classified based on a trypsin treatment number, which is evidence that the use of trypsin changes the properties of the cells.
Further, since the use of trypsin results in detachment of adhered cells from all surfaces of the culture vessel, a process for again adhering some of the cells is required after the use of trypsin, and the re-adhesion rate is low, namely 10% or less.
Examples of a process for preventing trypsin from being used include various processes such as a process of using the strong shear force of water, a scraping process in which a scraper is applied to a flat plate or a smoothly curved surface, a process of using temperature-reactive liquefaction/curable solid-liquid and liquid-solid materials as an adhesion material, and a process of using a collagenase instead of trypsin, but there are drawbacks in that the rate of cell recovery is low or inconsistent and in that a cell adhesion area is limited.
For example, in the case where the cells are detached from the cell adhesion beads using only the shear force of water, since a strong vortex must be used, the flow direction of water is not uniform, and accordingly, the recovery ratio is inconsistent, and the beads collide with each other, thus damaging cells sandwiched between the beads.
Further, in the case where the collagen adhesion material and the collagenase are used, since the enzyme does not affect cells positioned at the inside when the cells are layered in two or more layers, some of the cells may not be dissolved, or there is a risk of dissolving the cells owing to the function of the collagenase, which is similar to that of trypsin, during the period required to completely dissolve collagen, and accordingly, it is not easy to use the aforementioned technique.